1. Field of Invention
The invention relates generally to an application technique using holography, and more particularly, to a method of producing a projection holographic screen for displaying a three-dimensional color images.
2. Description of the Related Art
A projection holographic screen is a kind of holographic optical element that serves as a autostereoscopic image display screen which, being illuminated by the image projector, collects the image light into well defined viewing zones so that viewer can observe the displayed image if an eye is disposed within a viewing zone. To display the stereoscopic or multiview image it is necessary to use correspondingly two or more projectors each of them originating its own viewing zone. These viewing zones should be narrow enough to deliver one view of image to one viewer's eye and the viewing zone centers should be spaced apart from each other by an eye-to-eye distance (about 6.5 cm).
The method of producing the transmission type holographic screen has been proposed in the patent U.S. Pat. No. 6,211,977. For recording the holographic screen an elongate and narrow diff-using slit was used as an object and the diffuser position relative to the photoplate is mathematically set to make the light, being diffracted into viewing zone, to possess all spectral components within a visible range. The diffuser should be in form of the narrow slit to provide the sharp separation of the viewing zones for the left and right eyes, the slit should be inclined to the photoplate surface to provide appropriate focusing of all spectral components in the viewing zone, and the length of the slit should be big enough to provide overlapping in the viewing zone all spectral components of the visible spectrum.
The drawback of the described method consists of deterioration of the image coloration in the screen comers when screen size becomes big enough.